
NSF Org: |
CMMI Division of Civil, Mechanical, and Manufacturing Innovation |
Recipient: |
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Initial Amendment Date: | July 26, 2016 |
Latest Amendment Date: | July 17, 2023 |
Award Number: | 1636164 |
Award Instrument: | Standard Grant |
Program Manager: |
Joy Pauschke
jpauschk@nsf.gov (703)292-7024 CMMI Division of Civil, Mechanical, and Manufacturing Innovation ENG Directorate for Engineering |
Start Date: | September 1, 2016 |
End Date: | August 31, 2024 (Estimated) |
Total Intended Award Amount: | $390,001.00 |
Total Awarded Amount to Date: | $658,684.00 |
Funds Obligated to Date: |
FY 2019 = $77,431.00 FY 2021 = $39,153.00 FY 2022 = $76,050.00 FY 2023 = $76,049.00 |
History of Investigator: |
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Recipient Sponsored Research Office: |
1500 ILLINOIS ST GOLDEN CO US 80401-1887 (303)273-3000 |
Sponsor Congressional District: |
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Primary Place of Performance: |
CO US 80401-1887 |
Primary Place of
Performance Congressional District: |
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Unique Entity Identifier (UEI): |
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Parent UEI: |
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NSF Program(s): |
Engineering for Natural Hazard, ECI-Engineering for Civil Infr, GOALI-Grnt Opp Acad Lia wIndus, Special Initiatives |
Primary Program Source: |
01002324DB NSF RESEARCH & RELATED ACTIVIT 01001617DB NSF RESEARCH & RELATED ACTIVIT 01001920DB NSF RESEARCH & RELATED ACTIVIT 01002122DB NSF RESEARCH & RELATED ACTIVIT |
Program Reference Code(s): |
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Program Element Code(s): |
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Award Agency Code: | 4900 |
Fund Agency Code: | 4900 |
Assistance Listing Number(s): | 47.041 |
ABSTRACT
As the U.S. population continues to grow in urban communities, the demand for tall residential and mixed-use buildings in the range of eight to twenty stories continues to increase. Buildings in this height range are commonly built using concrete or steel. A recent new timber structural innovation, known as cross laminated timber (CLT), was developed in western Europe and is now being implemented around the world as a sustainable and low carbon-footprint alternative to conventional structural materials for tall buildings. However, an accepted and validated design method for tall CLT buildings to resist earthquakes has not yet been developed, and therefore construction of these tall wood buildings in the United States has been limited. This research will break this barrier by investigating a seismic design methodology for resilient tall wood buildings that can be immediately re-occupied following a design level earthquake and quickly repaired (compared to current building systems) after a large earthquake. Using the seismic design methodology developed in this project, the research team will work with practitioners across the engineering and architectural communities to design, build, and validate the performance of a ten-story wood building by conducting full-scale sub-assembly system testing at the National Science Foundation (NSF)-supported Natural Hazards Engineering Research Infrastructure (NHERI) experimental facility at Lehigh University, followed by full-scale tests at the NSF-supported NHERI outdoor shake table at the University of California at San Diego. This research will enable a new sustainable construction practice that is also cost-competitive, thereby increasing demands for engineered wood production, providing added value for forest resources, and enhancing job growth in the construction and forestry sectors. As part of the research, the experimental programs will serve to provide outreach to the public and stakeholders on issues related to seismic hazard mitigation, modern timber engineering, and resilient building concepts.
The goal of this research is to investigate and validate a seismic design methodology for tall wood buildings that incorporates high performance structural and non-structural systems. The methodology will quantitatively account for building resilience. This will be accomplished through a series of research tasks planned over a four-year period. These tasks will include mechanistic modeling of tall wood buildings with several variants of post-tensioned rocking CLT wall systems, fragility modeling of structural and non-structural building components that affect resilience, full-scale bi-directional testing of building sub-assembly systems, development of a resilience-based seismic design methodology, and finally a series of full-scale shake table tests of a ten-story CLT building specimen to validate the investigated design. The structural systems investigated will include post-tensioned CLT rocking walls in both monolithic and segmental rocking configurations. Implementing segmental rocking walls in a full building system will be a transformative concept that has yet to be realized physically. The rocking wall systems will be investigated under the context of holistic building behavior, including gravity systems and non-structural components. The research team will further push the boundary of existing performance-based seismic design by developing a design procedure that explicitly considers the time needed for the building to resume functionality after an earthquake. With the large-scale testing capacity provided by the NHERI experimental facilities, the design methodology will be experimentally validated, which will at the same time generate a landmark data set for tall wood buildings under dynamic loading that will be available to the broader research and practitioner community through the NHERI DesignSafe-ci.org Data Depot. The project will facilitate implementation of this new structural archetype by interfacing closely with practitioners in the Pacific Northwest interested in tall CLT buildings as a cost-competitive design option. Graduate and undergraduate students, including community college students, will actively participate in this research and gain valuable knowledge and experience, which will prepare them to become leaders in sustainable building practices using modern engineered wood materials.
PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH
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PROJECT OUTCOMES REPORT
Disclaimer
This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.
Wood has thousands of years of history as a sustainable building material but has been used mainly for low-rise building construction. Over the past 20 years, a new type of wood technology known as mass timber emerged and with it rapid construction approaches as a way to build taller with large engineered wood panel products. In fact the current building codes in the U.S. were updated to allow up to 18-story mass timber buildings. Around the world, a number of mass timber buildings over ten stories have been built. As this new building style is adopted by communities located within earthquake regions, a design method for tall wood buildings against earthquake hazards need to be developed.
In this project, the research team focused on finding a way to design and build tall earthquake-resilient wood buildings. This means that the building will not only protect people’s lives during large earthquakes, but also have minimal earthquake damage so that the building can be repaired quickly and relatively inexpensively following a major earthquake. A new design method called “resilience-based seismic design” was developed. Several innovative structural systems and details were invented from this project, including a new mass timber rocking wall system suitable for tall wood buildings. In order to verify and demonstrate the effectiveness of these systems, the research team (and their industry partners) designed and constructed a full-scale 10-story mass timber building on the world’s largest outdoor shake table (NHERI@UC San Diego facility). The 112 ft tall building was then tested using past earthquake records using the shake table and demonstrated excellent and resilient behavior. This 10-story test building represented the world's tallest full-scale shake table test ever.
During an approximately one-month testing period, the ten-story building successfully withstood 88 earthquake tests without structural damage or any need for repair. More than 40 of these 88 tests were conducted using earthquake input at or above the design code level. The building experienced no residual permanent deformation, with only cosmetic damage to the non-structural finishing materials, e.g. glass façade, drywall. The test results proved that tall wood mass timber buildings are a resilient option for regions with high earthquake hazard, such as the U.S. West Coast and Japan .
Through this project, a large number of graduate students received their training in large scale testing, numerical analysis, and performance-based design. Nine Ph.D. students participated in this project from 6 collaborating universities over a seven year period. The experimental research work also provided valuable research training and hands-on learning opportunities for seven M.S. students and 13 undergraduate students through the Research Experience for Undergraduate students program. In addition, this project featured extensive international collaboration, involving researchers and students from foreign universities including Kyoto University (Japan), University of L’Aquila (Italy), Imperial College London (UK). During the testing phase of the project, several public testing events for media and industry groups were held, providing an opportunity for both the general public and the engineering practitioner community to learn about this effective technology and design approach that can enable mass timber buildings throughout the U.S. and world in moderate to high seismic regions.
Results from this project has been well-received by the building industry and disseminated through a variety of channels. The 10-story testing effort was recognized by Engineering News Record (ENR) as one of the top 25 News Makers of 2023. The principle investigators have spoken at numerous national and international conferences and workshops. Journal and conference publications highlighting the research outcomes have been published or are under development. This project also provided strong support and comprehensive test data to support other follow-up research and development projects, such as the effort to introduce the mass timber rocking wall system into the seismic design standards, and design codes, in the U.S.
Last Modified: 11/04/2024
Modified by: Shiling Pei
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